The benefit of systemic steroids as adjunctive treatment in patients with severe community-acquired pneumonia (CAP) remains unclear. The present study aimed to evaluate the impact of corticosteroid treatment on mortality in patients with severe CAP. A retrospective, observational study of a cohort of patients hospitalised with severe CAP, classes IV and V of the Prognostic Severity Index score, was carried out. Information on epidemiological, clinical and laboratory data, and 30-day mortality was collected from medical charts. Of the 308 patients evaluated, 238 (77%) were treated with standard antimicrobial therapy and 70 (23%) received both antibiotics and systemic steroids. Clinical characteristics were similar between steroid and nonsteroid groups, except in the prevalence of male sex and the presence of chronic obstructive pulmonary disease. Systemic steroids were independently associated with a decreased mortality (odds ratio 0.287; 95% confidence interval 0.113-0.732), while severity of CAP (2.923; 1.262-6.770) was the only independent factor associated with increased mortality. Mortality decreased in the patients with severe CAP who received simultaneous administration of systemic steroids along with antibiotic treatment. Severity of community-acquired pneumonia remains the most important risk factor associated with increased mortality.